1. Field of the Invention
The present invention relates to a jet propulsion watercraft and a method of controlling the same.
2. Description of the Related Art
A jet propulsion watercraft including a so-called cruise control function has been known. During the cruise control function, the vessel body of the jet propulsion watercraft is controlled such that the jet propulsion watercraft cruises at a predetermined vessel velocity set while steering the jet propulsion watercraft. For example, a small planing boat disclosed in Japan Laid-open Patent Application Publication No. 2002-180861 includes a cruise control switch that controls the engine thereof so as to cruise at a predetermined vessel velocity or at a predetermined engine rotational speed in response to an operation of the cruise control switch.
When the vessel velocity of the above-described small planing boat is lower than a set velocity at a point of time that the cruise control switch is operated, the small planing boat accelerates until the vessel velocity thereof reaches the set velocity. It is preferable to stably control the acceleration of the small planing boat.
However, the weight of the jet propulsion watercraft varies depending on situations, even though the vessel body of the jet propulsion watercraft is unchanged. For example, the weight of the jet propulsion watercraft varies depending on a variation in the ballast water stored in a ballast tank or a variation in the number or weight of the crew. In the above-described small planing boat, acceleration during cruise control inevitably varies in accordance with variations in the weight of the jet propulsion watercraft. Therefore, it is difficult to maintain stable acceleration during cruise control.